<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>标签嵌套规则</title>
	</head>
<style type="text/css">
		.center1{
			float: left;
			border: #FF4400 3px solid;
			
		}
		.center{
			float: right;
			width: 400px;
			height: 500px;
			border: #FF4400 3px solid;
			
		}
	</style>
	<body>
		<div class="center1">
			行级只能套行级<br>
			a套a 除外<br>
			块级套所有<br>
			p套 div除外<br>
			
		</div>
		<a href="#"><a href="#"></a></a>
		<br>
		<p>
			<div ></div>
		</p>
	</body>
</html>